Canopies, typically comprising sheets of impermeable fabric or plastic, are widely used in various applications to shield people and/or objects from precipitation and/or sun. Common applications of such canopies occur in tents and umbrellas.
Unless such canopies are provided with vents, they are apt to be blown away, collapsed or inverted by gusts of wind. The problem with vents, however, is that they allow precipitation as well as wind to pass through the canopy.
Various solutions to this problem have been attempted as applied to umbrella canopies. All of these attempted solutions involve the use of multiple tiered canopies, usually with a smaller upper canopy covering the vent holes around the top of a larger lower canopy. Beach umbrellas, for example, typically incorporate this design. But, because the vented area in the lower canopy must be localized in this design, its effectiveness in withstanding winds from various directions is limited.
Other multi-tier designs adapted to rain umbrellas involve venting in both the upper and lower canopies, with the venting offset so that falling rain cannot pass directly through both layers. But, because the vent holes in the lower canopy are unobstructed, raindrops dripping along the lower canopy can still find their way into these vent holes and drip onto the person holding the umbrella. Also, because these designs lack a structure for maintaining a spaced relation between the upper and lower canopies, wind is apt to get trapped between them, causing disruption and/or damage to the canopies.